Curved cantilever design to reduce stress in mems actuator

ABSTRACT

The present disclosure relates integrated chip structure including a MEMS actuator. The MEMS actuator includes an anchor having a first plurality of branches extending outward from a central region of the anchor. The first plurality of branches respectively include a first plurality of fingers. A proof mass surrounds the anchor and includes a second plurality of branches extending inward from an interior sidewall of the proof mass. The second plurality of branches respectively include a second plurality of fingers interleaved with the first plurality of fingers as viewed in a top-view. One or more curved cantilevers are coupled between the proof mass and a frame wrapping around the proof mass. The one or more curved cantilevers have curved outer surfaces having one or more inflection points as viewed in the top-view.

REFERENCE TO RELATED APPLICATION

This Application claims the benefit of U.S. Provisional Application No.63/299,081, filed on Jan. 13, 2022, the contents of which are herebyincorporated by reference in their entirety.

BACKGROUND

Microelectromechanical systems, or MEMS, is a technology that integratesminiaturized mechanical and electro-mechanical elements on an integratedchip. MEMS devices are often made using micro-fabrication techniques. Inrecent years, MEMS devices have found a wide range of applications. Forexample, MEMS devices are found in hand held devices (e.g.,accelerometers, gyroscopes, digital compasses), pressure sensors (e.g.,crash sensors), micro-fluidic elements (e.g., valves, pumps), opticalswitches (e.g., mirrors), etc.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1A-1B illustrate some embodiments of an integrated chip structurecomprising a MEMS actuator having a proof mass coupled to a frame by oneor more curved cantilevers.

FIGS. 2A-2B illustrate some additional embodiments of an integrated chipstructure comprising a MEMS actuator having a proof mass coupled to aframe by one or more curved cantilevers.

FIGS. 3A-3B illustrates some embodiments showing operation of anactuator having one or more curved cantilevers within the disclosedintegrated chip structure.

FIGS. 4A-4B illustrate some embodiments of an integrated chip structurecomprising a MEMS actuator having a proof mass coupled to a frame by oneor more curved cantilevers.

FIGS. 5A-5C illustrate some embodiments of an integrated chip structurecomprising a MEMS actuator having a proof mass coupled to a frame by oneor more curved cantilevers.

FIG. 6 illustrates a top-view showing some embodiments of a disclosedcurved cantilever for a MEMS actuator.

FIG. 7 illustrates some additional embodiments of an integrated chipstructure comprising a MEMS actuator having a proof mass coupled to aframe by one or more curved cantilevers.

FIGS. 8-17 illustrate cross-sectional views showing some embodiments ofa method of forming an integrated chip structure comprising a MEMSactuator having a proof mass coupled to a frame by one or more curvedcantilevers.

FIG. 18 illustrates a flow diagram of some embodiments of a method offorming an integrated chip structure comprising a MEMS actuator having aproof mass coupled to a frame by one or more curved cantilevers.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Many modern day cameras comprise image stabilization technology. Imagestabilization technology is a technology that reduces blurringassociated with a motion (e.g., hand shaking) of an imaging deviceduring exposure. Typically, blurring occurs when an image sensor movesduring exposure. The movement causes light that is initially incidentupon one pixel to travel to adjacent pixels, thereby causing blurring.As resolutions of cameras increase, the size of pixel regions within thecameras decrease making blurring caused by movement (e.g., hand jitter)more evident in captured images.

Optical image stabilization (OIS) is one form of image stabilizationtechnology that can be used to mitigate blurring due to involuntarycamera movement (e.g., camera shaking). OIS senses a movement of acamera and subsequently compensates for the movement by controlling anoptical path between a target and an image sensor. The optical path maybe controlled by moving mechanical parts of a camera to ensure thatlight arrives at a same pixel of an image sensor even when movementoccurs.

Some cameras may comprise OIS systems having an image sensor integratedchip disposed on a MEMS actuator. The MEMS actuator is configured tomove the image sensor integrated chip in a manner that compensates formovement of the camera. The MEMS actuator may comprise a frame that iscoupled to a package box. A proof mass is coupled to the frame by way ofone or more straight cantilevers. The proof mass is further coupled tothe image sensor integrated chip and is configured to move duringoperation to compensate for the movement of the camera. It has beenappreciated that during extreme movements of the camera, a stress on theone or more straight cantilevers may be large. For example, when beingdropped from a height of approximately 1.5 meters, the one or morestraight cantilevers may undergo a stress that is on the order of 10⁶MPa (Mega Pascals). Such large stress may break the one or more straightcantilevers of the MEMS actuator, thereby rending the OIS system of thecamera inoperable.

The present disclosure relates to an integrated chip structurecomprising a MEMS (microelectromechanical systems) actuator having aproof mass coupled to a frame by one or more curved cantilevers. In someembodiments, the MEMS actuator comprises an anchor that is coupled to abase substrate. The anchor comprises a first plurality of branchesrespectively having a first plurality of fingers. A proof mass surroundsthe anchor and comprises a second plurality of branches respectivelyhaving a second plurality of fingers that are interleaved with the firstplurality of fingers as viewed in a top-view. One or more curvedcantilevers are coupled between the proof mass and a frame, which wrapsaround the proof mass. The one or more curved cantilevers comprisecurved outer surfaces having one or more inflection points as viewed inthe top-view. The curved outer surfaces of the one or more curvedcantilevers reduce a stress on the one or more curved cantilevers duringextreme movements of the MEMS actuator. By reducing a stress on the oneor more curved cantilevers during extreme movements, the disclosed MEMSactuator is able to provide for an improved reliability under real worldconditions (e.g., when dropped).

FIG. 1A illustrates a top-view 100 of some embodiments of a MEMSactuator 101 having a proof mass coupled to a frame by one or morecurved cantilevers.

The MEMS actuator 101 comprises a proof mass 102 separated from a frame104 by one or more first openings 105. One or more curved cantilevers106 traverse the one or more first openings 105 to couple the proof mass102 to the frame 104. In some embodiments, the frame 104 wraps aroundthe proof mass 102 in a first continuous loop (e.g., a first unbrokenloop). The proof mass 102 is further separated from an anchor 108 by oneor more second openings 107. In some embodiments, the proof mass 102wraps around the anchor 108 in a second continuous loop (e.g., a secondunbroken loop). In some embodiments, the MEMS actuator 101 comprises anelectrostatic actuator. In some embodiments, the MEMS actuator 101comprises a comb actuator (e.g., an electrostatic comb actuator), suchas polysilicon suspended comb. In such embodiments, the anchor 108 has afirst plurality of fingers that are interleaved with a second pluralityof fingers of the proof mass 102.

The one or more curved cantilevers 106 comprise curved outer surfaces(e.g., curved outer sidewalls). In some embodiments, the curved outersurfaces may comprise a winding shape as viewed in the top-view 100 ofthe MEMS actuator 101. In some embodiments, the one or more curvedcantilevers 106 may comprise a plurality of turning points separated bya plurality of inflection points. For example, the one or more curvedcantilevers 106 may respectively comprise a first maximum turning point(e.g., a local peak) on a side of a curved cantilever facing the proofmass 102, a first minimum turning point (e.g., a local trough) on theside of the curved cantilever facing the proof mass 102, and aninflection point between the first maximum turning point and the firstminimum turning point. In some embodiments, the one or more curvedcantilevers may respectively comprise multiple maximum turning points,multiple minimum turning points, and multiple inflection points onopposing sides of a curved cantilever.

It has been appreciated that the curved outer surfaces (e.g., sidewalls)reduce a localized stress on the one or more curved cantilevers 106during movement of the MEMS actuator 101. For example, when beingdropped from a height of approximately 1.5 meters, the one or morecurved cantilevers 106 may undergo a stress that is at least two ordersof magnitude smaller than that of straight cantilevers (e.g., that is onthe order of 10⁴ MPa). By reducing localized stress on the one or morecurved cantilevers 106, a reliability of the MEMS actuator 101 can beimproved.

FIG. 1B illustrates a cross-sectional view of some embodiments of anintegrated chip structure 110 comprising a MEMS actuator 101 having aproof mass 102 coupled to a frame 104 by one or more curved cantilevers.In some embodiments, the top-view of the MEMS actuator 101 shown in FIG.1A may be taken along cross-sectional line A-A′ of FIG. 1B.

The integrated chip structure 110 comprises a semiconductor structure112 disposed onto the MEMS actuator 101. In various embodiments, thesemiconductor structure 112 may comprise an optical sensor (e.g., animage sensor integrated chip), an optical component (e.g., a mirror,lens, or the like), a sensor (e.g., for an atomic force microscope), anRF (radio frequency) switch, or the like.

In some embodiments, the semiconductor structure 112 is coupled to theproof mass 102 of the MEMS actuator 101. In some embodiments, the frame104 of the MEMS actuator is coupled to a housing 114 that surrounds theMEMS actuator 101 and the semiconductor structure 112. During operation,the proof mass 102 is configured to move in response to an appliedsignal to spatially move the semiconductor structure 112. In variousembodiments, the proof mass of the MEMS actuator 101 can move in amanner that changes a height and/or a pitch (e.g., slope) of thesemiconductor structure 112. The movements can be detected by acapacitive read-out scheme.

FIG. 2A illustrates a cross-sectional view some additional embodimentsof an integrated chip structure 200 comprising a MEMS actuator having aproof mass coupled to a frame by one or more curved cantilevers.

The integrated chip structure 200 comprises a MEMS actuator 101 having aproof mass 102 surrounded by a frame 104 and an anchor 108 surrounded bythe proof mass 102. An image sensor integrated chip 202 is disposed onthe proof mass 102. In some embodiments, the image sensor integratedchip 202 may be coupled to the proof mass 102 by way of one or morefirst coupling elements 204. In some embodiments, the one or more firstcoupling elements 204 may comprise conductive structures (e.g., solderbumps, vertical wire bonds, a wire stud, or the like) and/or a polymer.In some embodiments, the one or more first coupling elements 204 maycomprise a conducive structure (e.g., a vertical wire bond) surroundedby an encapsulant (e.g., an epoxy resin, an epoxy resin with filler,epoxy acrylate, a polymer, or the like).

The image sensor integrated chip 202 comprises one or more pixelsregions respectively including an image sensing element configured toconvert electromagnetic radiation (e.g., visible light, ultravioletradiation, or the like) into an electrical signal. In some embodiments,the image sensor integrated chip 202 may comprise a CMOS (complementarymetal-on-oxide) image sensor (CIS). In some embodiments, the imagesensing element may comprise a photodiode, a photodetector, or the like.

In some embodiments, the MEMS actuator 101 and the image sensorintegrated chip 202 are disposed within a package box 206 (e.g., acamera module). In such embodiments, the package box 206 comprises ahousing 208 that surrounds the MEMS actuator 101 and the image sensorintegrated chip 202. In some embodiments, the housing 208 is attached toa base substrate 210. In some embodiment, the base substrate 210 maycomprise a printed circuit board (PCB). The frame 104 of the MEMSactuator 101 is coupled to the housing 208 of the package box 206. Insome embodiments, the frame 104 is laterally and physically coupled toone or more sidewalls of the housing 208. By further coupling the frame104 to the proof mass 102 by way of the one or more curved cantilevers,the one or more curved cantilevers are able to provide support for theproof mass 102 when the package box 206 is moved (e.g., when the packagebox 206 is dropped), thereby protecting the proof mass 102 fromexcessive unwanted movement that may damage the proof mass 102.

In various embodiments, the MEMS actuator 101 may be further coupled tothe base substrate 210 by way of one or more second coupling elements212. In some embodiments, the anchor 108 of the MEMS actuator 101 may beattached to the base substrate 210 by the one or more second couplingelements 212. In some embodiments, the one or more second couplingelements 212 may comprise conductive structures (e.g., solder bumps,vertical wire bonds, a wire stud, or the like) and/or a polymer. In someembodiments, the one or more second coupling elements 212 may comprise aconducive structure (e.g., a vertical wire bond) surrounded by anencapsulant (e.g., an epoxy resin, an epoxy resin with filler, epoxyacrylate, a polymer, or the like). In some embodiments, the anchor 108of the MEMS actuator 101 may be rigidly coupled to the base substrate210 by the one or more second coupling elements 212. In some additionalembodiments (not shown), one or more additional coupling elements (e.g.,vertical wire bonds, wire bonds, or the like) may be configured toelectrically couple the proof mass 102 and/or the image sensorintegrated chip 202 to the base substrate 210.

An optical system 214 is arranged along an upper surface of the packagebox 206 and over the image sensor integrated chip 202. The opticalsystem 214 comprises one or more lenses and/or mirrors. Duringoperation, the optical system 214 is configured to focus incidentradiation 216 onto one or more pixel regions of the image sensorintegrated chip 202.

FIG. 2B illustrates some embodiments of a top-view 218 of the MEMSactuator 101 taken along cross-sectional line A-A′ of FIG. 2A.

As shown in top-view 218, the proof mass 102 of the MEMS actuator 101 iscoupled to the frame 104 by way of one or more curved cantilevers 106.In some embodiments, the proof mass 102 has a maximum length 220extending between outermost edges of the proof mass 102. In someembodiments, the maximum length 220 of the proof mass 102 is in a rangeof between approximately 100 microns (μm) and approximately 2000 μm,between approximately 200 μm and approximately 1200 μm, or other similarvalues. In some embodiment, a ratio of the maximum length 220 of theproof mass 102 to a maximum length of the one or more curved cantilevers106 is between approximately 1 and approximately 4, betweenapproximately 1.15 and approximately 3.2, or other similar values.

During operation, unwanted movement of the package box (e.g., 206 ofFIG. 2A) can cause a focal point of the optical system 214 to move,thereby causing incident radiation to strike different pixel regionswithin the image sensor integrated chip 202. The MEMS actuator 101 isconfigured to move the image sensor integrated chip 202 in response tothe unwanted movements of the package box 206 to reduce the effects ofmovement on the image sensor integrated chip 202 (e.g., reduce blurringof an image by minimizing the movement of incident radiation betweenpixels) and therefore stabilize an image being captured by the imagesensor integrated chip 202. For example, when a change in position ofthe image sensor integrated chip 202 is detected a signal is applied tothe anchor 108 and/or the proof mass 102 of the MEMS actuator 101. Thesignal moves the proof mass 102 and the image sensor integrated chip 202to mitigate the effects of the movement (e.g., in a direction oppositeto the direction of the camera shake thereby stabilizing an imagecaptured by the image sensor integrated chip 202).

For example, FIGS. 3A-3B illustrate some embodiments showing operationof a disclosed MEMS actuator 101 having one or more curved cantilevers.

As shown in cross-sectional view 300 and top-view 302 of FIG. 3A, at afirst time the MEMS actuator 101 holds the image sensor integrated chip202 at a first angle θ₁ with respect to a line 301 that is normal to anupper surface of the base substrate 210 (i.e., that is oriented at anangle ϕ of 90 degrees with respect to the upper surface of the basesubstrate 210). The first angle θ₁ is achieved by having a firstdistance d₁ between interleaved fingers within a first quadrant 304 asurrounding a center of the anchor 108, a second distance d₂ betweeninterleaved fingers within a second quadrant 304 b surrounding thecenter of the anchor 108, a third distance d₃ between interleavedfingers within a third quadrant 304 c surrounding the center of theanchor 108, and a fourth distance d₄ between interleaved fingers withina fourth quadrant 304 d surrounding the center of the anchor 108. Insome embodiments, the first angle θ₁ may be approximately 90 degrees. Insuch embodiments, a plurality of outer edges of the proof mass 102 areat a substantially same distance over the base substrate 210.

As the package box 206 moves (e.g., due to a person's hand shaking whileholding a camera), the MEMS actuator 101 is configured to move the imagesensor integrated chip 202 to compensate for the movement and therebymitigate blurriness of an image captured by the image sensor integratedchip 202. For example, as shown in cross-sectional view 306 and top-view308 of FIG. 3B, at a second time the MEMS actuator 101 may compensatefor movement of the package box 206 by moving the image sensorintegrated chip 202 to be oriented at a second angle θ₂ with respect toa line 307 that is normal to an upper surface of the base substrate 210.To move the image sensor integrated chip 202 to compensate for themovement, the distances between interleaved fingers within one or moreof the quadrants 304 a-304 d changes. For example, a distance betweeninterleaved fingers within the second quadrant 304 b may change from thesecond distance d₂ to a modified second distance d₂′. The change in thesecond distance changes a height of a first edge of the proof mass 102,thereby rotating the proof mass 102 and the image sensor integrated chip202. In some embodiments, the distance between interleaved fingers maybe changed by applying an electrical signal (e.g., a voltage) to theanchor 108 and/or the proof mass 102.

FIG. 4A illustrates a top-view of some additional embodiments of anintegrated chip structure 400 comprising a MEMS actuator having a proofmass coupled to a frame by one or more curved cantilevers.

The integrated chip structure 400 comprises a MEMS actuator 101 havingan anchor 108 surrounded by a proof mass 102. The proof mass 102 isfurther surrounded by a frame 104. The anchor 108 comprises across-shape having a first plurality of branches 108 b extending outwardfrom a central region 108 c. In some embodiments, each of the firstplurality of branches 108 b comprises a first segment 109 a extending ina first direction and a second segment 109 b extending in a seconddirection perpendicular to the first direction. In some embodiments,each of the first plurality of branches 108 b comprises a bend having a90 degree angle. A first plurality of fingers 111 extend outward fromeach of the first plurality of branches 108 b of the anchor 108.

In some embodiments, a width of the first segment 109 a increases as adistance from the central region 108 c increases. For example, the widthof the first segment 109 a of one of the first plurality of branches 108b may increase from a first width 402 close to the central region 108 cto a second width 404 at a greater distance from the central region 108c. In some embodiments, a width of the second segment 109 b alsoincreases as a distance from the first segment 109 a increases. Forexample, the width of the second segment 109 b of one of the firstplurality of branches 108 b may increase from a third width 406 close tothe first segment 109 a to a fourth width 408 at a greater distance fromthe first segment 109 a.

The proof mass 102 surrounds the anchor 108. In some embodiments, theproof mass 102 comprises a ring region 102 r that wraps around theanchor 108 in a closed loop (e.g., an unbroken loop). A second pluralityof branches 102 b extend inward from interior sidewalls of the ringregion 102 r of the proof mass 102 that face the anchor 108. A secondplurality of fingers 103 extend outward from each of the secondplurality of branches 102 b. The first plurality of fingers 111 areinterleaved with the second plurality of fingers 103.

One or more curved cantilevers 106 couple the proof mass 102 to theframe 104. The one or more curved cantilevers 106 comprise curved outersurfaces having a plurality of inflection points 410. In someembodiments, the one or more curved cantilevers 106 comprise sidewallshaving the plurality of inflection points 410, as viewed in the top-viewof FIG. 4A. In some embodiments, the one or more curved cantilevers 106extend laterally past sidewalls of one or more the second plurality ofbranches 102 b.

In some embodiments, the proof mass 102 may have four outer edgescoupled to the frame 104 by four curved cantilevers respectivelydisposed along one of the four outer edges of the proof mass 102. Insome such embodiments, the anchor 108 may comprise four branchesextending outward from a central region 108 c of the anchor 108, and theproof mass 102 may comprise four branches extending inward from the ringregion 102 r. In some embodiments, the anchor 108 comprises a firstbranch extending outward from the central region 108 c to the right, asecond branch extending outward from the central region 108 c to theleft, a third branch extending outward from the central region 108 cdownward, and a fourth branch extending outward from the central region108 c upward, as viewed in a top-view. In some embodiments, the fourbranches are orientated at approximately 90 degrees from one another. Insuch embodiments, the first plurality of fingers 111 are interleavedwith the second plurality of fingers 103 within a first quadrant 304 a,a second quadrant 304 b, a third quadrant 304 c, and a fourth quadrant304 d surrounding the central region 108 c of the anchor 108.

In some embodiments, the one or more curved cantilevers 106 extend froma surface of the proof mass 102 that faces a first direction to asurface of the frame 104 that faces an opposing second direction. Insome embodiments, the one or more curved cantilevers 106 may be coupledto the proof mass 102 and to the frame 104 by way of an absorber 412.The absorber 412 is configured to dampen vibrations on the one or morecurved cantilevers 106, thereby reducing a stress on the one or morecurved cantilevers.

FIG. 4B illustrates a top-view 414 of some embodiments of an absorber412 coupled to the one or more curved cantilevers 106. As shown intop-view 414, the absorber 412 may comprise a receiving element 416 thatis coupled to the one or more curved cantilevers 106. The receivingelement 416 is coupled to a damping element 420 by way of an elasticspring 418. During operation, the damping element 420 may move inresponse to stress due to an elastic line 422 coupled to a base 424. Theelastic spring 418 may further move in response to the stress, therebyreducing a stress upon ends of the one or more curved cantilevers 106.

FIG. 5A illustrates a top-view 500 of some additional embodiments of anintegrated chip structure comprising a MEMS actuator having a proof masscoupled to a frame by one or more curved cantilevers.

The MEMS actuator 101 comprises a proof mass 102 coupled to a frame 104by way of one or more curved cantilevers 106. The proof mass 102surrounds an anchor 108. The proof mass 102 has a first plurality offingers and the anchor 108 comprises a second plurality of fingers thatare interleaved with the first plurality of fingers.

The proof mass 102 comprises a proof mass central region 502 asurrounded by proof mass exterior regions respectively comprising aproof mass core 506 a and a proof mass dielectric liner 504 a. The frame104 comprises a frame central region 502 b and one or more frameexterior regions respectively comprising a frame core material 506 bsurrounded by a frame dielectric liner 504 b. The one or more curvedcantilevers 106 respectively comprise a cantilever central region 502 csurrounded by cantilever exterior regions respectively comprising acantilever core material 506 c surrounded by a cantilever dielectricliner 504 c. The anchor 108 comprises an anchor central region 502 dsurrounded by anchor exterior regions respectively comprising an anchorcore material 506 d surrounded by an anchor dielectric liner 504 d.

In some embodiments, the central regions 502 a-502 d may comprise asemiconductor material (e.g., silicon, polysilicon, crystallizedsilicon, doped silicon, or the like). In some embodiments, thedielectric liners 504 a-504 d may comprise an oxide (e.g., silicondioxide), a nitride (e.g., silicon nitride, silicon oxynitride, etc.), acarbide (e.g., silicon carbide, silicon oxycarbide, etc.), or the like.In some embodiments, the core materials 506 a-506 d may comprisepolysilicon. In some embodiments, the core materials 506 a-506 d mayextend to an uppermost surface of the dielectric liners 504 a-504 dand/or the central regions 502 a-502 d.

In some embodiments, the semiconductor material, the core materials, andthe dielectric liners may respectively have a Young's modulus of greaterthan approximately 100 GPa (Giga Pascals), greater than approximately120 GPa, greater than approximately 150 GPa, or other similar values.For example, in some embodiments, the dielectric liner may have aYoung's modulus of between approximately 150 GPa and approximately 200GPa, the semiconductor material may have a Young's modulus of betweenapproximately 150 GPa and approximately 200 GPa, and the core materialmay have a Young's modulus of between approximately 120 GPa andapproximately 200 GPa. The relatively high Young's modulus of thesemiconductor material, the core materials, and the dielectric linersimproves the one or more curved cantilevers 106 ability to undergostress, thereby further improving a reliability of the one or morecurved cantilevers 106.

Top-view 508 illustrates an enlarged view of a portion of the MEMSactuator 101, further illustrating the central regions 502 a-502 c, thecore materials 506 a-506 c, and the dielectric liners 504 a-504 c withinthe proof mass 102, the one or more curved cantilevers 106, and theframe 104.

FIG. 5B illustrates a cross-sectional view 510 of the MEMS actuator 101taken along line 509 of FIG. 5A. As shown in cross-sectional view 510,the frame 104, the proof mass 102, the one or more curved cantilevers106, and the anchor 108 are arranged within a semiconductor layer 512(e.g., a MEMS substrate). The dielectric liners 504 a-504 d completelycover sidewalls of the central regions 502 a-502 d and the corematerials 506 a-506 d.

The one or more curved cantilevers 106 are separated from the frame 104and the proof mass 102 by way of one or more first openings 105. Theproof mass 102 is further separated from the anchor 108 by way of one ormore second openings 107. The one or more first openings 105 and the oneor more second openings 107 are respectively defined by sidewalls of thedielectric liners 504 a-504 d.

In some embodiments, a dielectric cap 514 may be disposed over thecentral regions 502 a-502 d, the dielectric liners 504 a-504 d, and thecore materials 506 a-506 d within the frame 104, the proof mass 102, theone or more curved cantilevers 106, and the anchor 108. In someembodiments, the dielectric cap 514 may comprise an oxide (e.g., silicondioxide), a nitride (e.g., silicon nitride, silicon oxynitride, etc.), acarbide (e.g., silicon carbide, silicon oxycarbide, etc.), or the like.In such embodiments, the semiconductor layer 512, the dielectric liners504 a-504 d, and the core materials 506 a-506 d may continuously extendfrom a bottommost surface of the MEMS actuator 101 to the dielectric cap514. In other embodiments, the dielectric cap 514 may be omitted so thatthe semiconductor layer 512, the dielectric liners 504 a-504 d, and thecore materials 506 a-506 d continuously extend from a bottommost surfaceof the MEMS actuator 101 to a topmost surface of the MEMS actuator 101.

FIG. 5C illustrates a three-dimensional view 516 of a portion 511 of theMEMS actuator 101 shown in FIG. 5A. As shown in three-dimensional view516, the one or more curved cantilevers 106 may have a thickness 518that is approximately equal to a thickness of the proof mass 104.

FIG. 6 illustrates a top-view showing some embodiments of a curvedcantilever 600.

The curved cantilever 600 comprises a wavy profile having opposing sidescomprising curved segments. In some embodiments, the curved segments areseparated by substantially straight regions. In other embodiments, thecurved segments meet at a plurality of inflection points arranged alongopposing sides of the curved cantilever. The curved cantilever 600 has alength 602 that is in a range of between approximately 200 microns (μm)and approximately 4000 μm, between approximately 230 μm andapproximately 3840 μm, or other similar values. In some embodiments, thecurved cantilever 600 may have a wavelength 604 (e.g., a length betweenpeaks (maximum turning points) and/or troughs (minimum turning points)of the curved cantilever 600) that is in a range of betweenapproximately 100 μm and approximately 500 μm, between approximately 200μm and approximately 400 μm, or other similar values. In someembodiments, the curved cantilever 600 may have a wave height 606 (e.g.,a height between a peak and a neighboring trough of the curvedcantilever 600) that is in a range of between approximately 5 μm andapproximately 150 μm, between approximately 10 μm and approximately 110μm, or other similar values.

Due to the curvature of the curved cantilever 600, different locationson the curved cantilever 600 undergo different amounts of stress duringmovement. For example, in some embodiments, the curvature of the curvedcantilever 600 may cause a first stress 608 along an outer edge of thecurved cantilever that is near an inflection point, which is larger thana second stress 610 along an outer edge of the curved cantilever that isnear a local maximum turning point and/or minimum turning point of thecurved cantilever 600. In some embodiments, the curvature of the curvedcantilever 600 may cause a third stress 612 in a central region of thecurved cantilever 600 that is greater than the second stress 610. Insome embodiments, the second stress 610 or the third stress 612 may be amaximum stress on the curved cantilever 600 that is less thanapproximately 2×10⁴ mega Pascals (MPa), less than approximately 1.8×10⁴MPa, approximately 1.743×10⁴ MPa, or other similar values, such asapproximately 1.158×10³ MPa, in a drop test with 250 grams in weight and1.5 meters in height. Because the maximum stress on the curvedcantilever 600 is less than that of a straight cantilever (e.g., lessthan approximately 1×10⁶ MPa), the curved cantilever 600 is less likelyto break during high stress (e.g., being dropped) on the curvedcantilever 600 thereby improving a reliability of a disclosed MEMSactuator.

FIG. 7 illustrates some additional embodiments of an integrated chipstructure 700 comprising a MEMS actuator having a proof mass coupled toa frame by one or more curved cantilevers.

The integrated chip structure 700 comprises a package box 206 (e.g., acamera module) disposed over a base substrate 210. An optical system 214is arranged along an upper surface of the package box 206. In someembodiments, the optical system 214 may comprise an objective lens 214 aand a floating lens 214 b disposed between the objective lens 214 a andthe image sensor integrated chip 202. A MEMS actuator 101 is disposedwithin the package box 206 below the optical system 214. The MEMSactuator 101 comprises a frame 104 coupled to sidewalls of the packagebox 206. In some embodiments, a dielectric liner 504 arranged along anoutermost sidewall of the MEMS actuator 101 may be coupled to a sidewallof the package box 206 (e.g., by an adhesive material). In otherembodiments (not shown), a semiconductor material arranged along anoutermost sidewall of the MEMS actuator 101 may be coupled to a sidewallof the package box 206.

An image sensor integrated chip 202 is disposed on the MEMS actuator 101and between the MEMS actuator 101 and the optical system 214. The imagesensor integrated chip 202 comprises an image sensing element 710disposed within the substrate 702. In some embodiment, the image sensingelement 710 may comprise a photodiode including a first region having afirst doping type (e.g., n-type doping) and an adjoining second regionhaving a second doping type (e.g., p-type doping) that is different thanthe first doping type. A transistor gate structure 704 is arranged alonga first-side of the substrate 702. In some embodiments, the transistorgate structure 704 may correspond to a transfer transistor. In suchembodiments, the transistor gate structure 704 is laterally arrangedbetween the image sensing element 710 and a floating diffusion well 712.The transistor gate structure 704 is configured to control the transferof charge from the image sensing element 710 (e.g., a photodiode) to thefloating diffusion well 712.

A dielectric structure 706 is disposed along the first-side of thesubstrate 702. The dielectric structure 706 comprises a plurality ofstacked inter-level dielectric (ILD) layers. In some embodiments, aplurality of conductive interconnects 708 (e.g., conductive contacts,interconnect wires, and/or interconnect vias) are disposed within thedielectric structure 706.

A dielectric planarization structure 714 may be arranged along a secondside of the substrate 702. The dielectric planarization structure 714has a substantially planar surface facing away from the substrate 702.In various embodiments, the dielectric planarization structure 714 maycomprise one or more stacked dielectric layers (e.g., an oxide, anitride, or the like). A grid structure 716 is disposed on thedielectric planarization structure 714. In various embodiments, the gridstructure 716 may comprise a metal (e.g., aluminum, cobalt, copper,silver, gold, tungsten, etc.) and/or a dielectric material (e.g., SiO₂,SiN, etc.). A color filter 718 is arranged within an opening in the gridstructure 716. The color filter 718 is configured to selectivelytransmit specific wavelengths of incident radiation. For example, thecolor filter 718 may transmit radiation having wavelengths within afirst range (e.g., corresponding to green light), while a second colorfilter (not shown) may transmit radiation having wavelengths within asecond range (e.g., corresponding to red light) different than the firstrange, etc. A micro-lens 720 is arranged over the color filter 718. Themicro-lens 720 is laterally aligned with the color filter 718 and isconfigured to focus the incident radiation (e.g., light) towards theimage sensing element 710.

In some embodiments, a MEMS gyroscope 722 and/or a MEMS accelerometer724 may be disposed on the base substrate 210. The MEMS gyroscope 722and/or the MEMS accelerometer 724 are configured to detect and/ormeasure movement of the package box 206. In some embodiments, the MEMSgyroscope 722 and/or the MEMS accelerometer 724 may be coupled to acontrol circuitry 726 disposed on the base substrate 210. The controlcircuitry 726 is configured to send a signal to the MEMS actuator 101based on detected movement sensed by the MEMS gyroscope 722 and/or theMEMS accelerometer 724. The signal is configured to cause the MEMSactuator 101 to move in a manner that mitigates an effect of themovement of the package box 206 on the image sensor integrated chip 202,so as to mitigate blurriness in images captured by the image sensorintegrated chip 202.

FIGS. 8-17 illustrate cross-sectional views 800-1700 showing someembodiments of a method of forming an integrated chip structurecomprising a MEMS actuator having a proof mass coupled to a frame by oneor more curved cantilevers. Although FIGS. 8-17 are described inrelation to a method, it will be appreciated that the structuresdisclosed in FIGS. 8-17 are not limited to such a method, but insteadmay stand alone as structures independent of the method.

As shown in cross-sectional view 800 (taken along line 812) and top-view810 (taken along line 808) of FIG. 8 , a substrate 802 is provided. Thesubstrate 802 comprises a lower semiconductor layer 804 separated from asemiconductor layer 512 by an insulating layer 806. In some embodiments,the lower semiconductor layer 804 and the semiconductor layer 512 maycomprise silicon, germanium, gallium, or the like. In some embodiments,the insulating layer 806 may comprise an oxide (e.g., silicon oxide), anitride (e.g., silicon oxynitride), or the like.

In some embodiments, the lower semiconductor layer 804 may be a firstsubstrate comprising a first semiconductor body, a handle wafer, or thelike. In some embodiments, the semiconductor layer 512 may be a secondsemiconductor body, a MEMS wafer, or the like. In some embodiments, thesubstrate 802 may be provided by forming the insulating layer 806 overthe lower semiconductor layer 804 and subsequently bonding thesemiconductor layer 512 to the insulating layer 806. In someembodiments, the insulating layer 806 may be formed by a thermaloxidation process, such as a wet thermal oxidation process or a drythermal oxidation process. During such embodiments, the lowersemiconductor layer 804 is placed in a furnace and heated to atemperature typically ranging between approximately 800 degrees Celsius(° C.) and approximately 1200° C. in the presence of oxygen to form theinsulating layer 806. In other embodiments, the insulating layer 806 canbe formed by a spin-on process, a plasma vapor deposition (PVD) process,a chemical vapor deposition (CVD) process, an atomic layer deposition(ALD) process, or other techniques. In some embodiments, thesemiconductor layer 512 is bonded to a top surface of the insulatinglayer 806 through a fusion bonding process.

As shown in cross-sectional view 900 (taken along line 812) and top-view928 (taken along line 808) of FIG. 9 , the semiconductor layer 512 ispatterned to form a plurality of trenches that extend into thesemiconductor layer 512 to define a cantilever region 902, a frameregion 904, a proof mass region 906, and an anchor region 908. Thecantilever region 902, the frame region 904, the proof mass region 906,and the anchor region 908 are separated from one another by theplurality of trenches. In some embodiments, the cantilever region 902,the frame region 904, the proof mass region 906, and the anchor region908 may also be separated from one another by sacrificial regions910-914. The cantilever region 902 is defined by curved sidewalls of thesemiconductor layer 512 that continuously extend between the frameregion 904 and the proof mass region 906.

In some embodiments, the plurality of trenches comprise a plurality ofcurved trenches 916 on opposing sides of the cantilever region 902, afirst plurality of straight trenches 918 on opposing sides of the proofmass region 906, a second straight trench 920 between the frame region904 and the plurality of curved trenches 916, and a third straighttrench 922 between the anchor region 908 and the first plurality ofstraight trenches 918. The plurality of curved trenches 916 areseparated from the first plurality of straight trenches 918 by a firstsacrificial region 910 and from the second straight trench 920 by asecond sacrificial region 912. The first plurality of straight trenches918 are separated from the third straight trench 922 by a thirdsacrificial region 914. In some embodiments, the plurality of curvedtrenches 916, the first plurality of straight trenches 918, the secondstraight trench 920, and the third straight trench 922 have bottomsdefined by horizontally extending surfaces of the semiconductor layer512.

In some embodiments, the plurality of curved trenches 916, the firstplurality of straight trenches 918, the second straight trench 920, andthe third straight trench 922 are respectively defined by sidewalls anda horizontally extending surface of the semiconductor layer 512. In someembodiments, the plurality of curved trenches 916, the first pluralityof straight trenches 918, the second straight trench 920, and the thirdstraight trench 922 are formed by a lithography process that forms apatterned masking layer 924 over the semiconductor layer 512 and thatsubsequently etches exposed areas of the semiconductor layer 512 with anetchant 926. In some embodiments, the etchant 926 may comprise a dryetchant. In some embodiments, the dry etchant may comprise a fluorinebased etching chemistry. For example, the dry etchant may have anetching chemistry comprising carbon tetrafluoride (CF₄),trifluoromethane (CHF₃), octafluorocyclobutane (C₄F₈), or the like. Inother embodiments, the dry etchant may comprise an etching chemistrycomprising chlorine (Cl₂), HB₄, Argon (Ar), or the like.

As shown in cross-sectional view 1000 (taken along line 812) andtop-view 1004 (taken along line 808) of FIG. 10 , one or more fillmaterials are formed within the plurality of trenches (e.g., theplurality of curved trenches 916, the first plurality of straighttrenches 918, the second straight trench 920, and the third straighttrench 922). The one or more fill materials completely fill theplurality of trenches. In some embodiments, the one or more fillmaterials may comprise a dielectric liner 504 formed along interiorsurfaces of the plurality of trenches and a core material 506 arrangedon the dielectric liner 504. In some embodiments, the dielectric liner504 may comprise an oxide (e.g., silicon oxide), a nitride (e.g.,silicon nitride), or the like. In some embodiments, the core material506 may comprise polysilicon or the like. In some embodiments, the oneor more fill materials may comprise a Young's modulus that is greaterthan or equal to approximately 120 GPa.

In some embodiments, the dielectric liner 504 may be formed by a thermaloxidation process. In such embodiments, the semiconductor layer 512 maybe exposed to a high temperature (e.g., greater than or equal toapproximately 700° C., greater than or equal to approximately 800° C.,between approximately 900° C. and approximately 1100° C., or othersimilar values). In some embodiments, the semiconductor layer 512 may beexposed to the high temperature in a presence of water vapor. Thethermal oxidation process forms an oxide along interior surfaces of theplurality of trenches. The core material 506 is subsequently formed byway of a deposition process onto the dielectric liner 504 and within theplurality of trenches. In various embodiments, the deposition processmay comprise a PVD process, a CVD process, a PE-CVD process, an ALDprocess, or the like. In some embodiments, a planarization process(e.g., a chemical mechanical planarization (CMP) process) may beperformed along line 1002 to remove excess of the semiconductor materialfrom over a top of the semiconductor layer 512.

As shown in cross-sectional view 1100 (taken along line 812) andtop-view 1102 (taken along line 808) of FIG. 11 , a dielectric cap 514is formed over the semiconductor layer 512. The dielectric cap 514covers the cantilever region 902, the frame region 904, the proof massregion 906, and the anchor region 908. The dielectric cap 514 exposesthe first sacrificial region 910, the second sacrificial region 912, andthe third sacrificial region 914. In various embodiments, the dielectriccap 514 comprises an oxide (e.g., silicon oxide), a nitride (e.g.,silicon nitride, silicon oxynitride, etc.), a carbide (e.g., siliconcarbide, silicon oxycarbide, etc.), or the like.

As shown in cross-sectional view 1200 (taken along line 812) andtop-view 1206 (taken along line 808) of FIG. 12 , a release etchingprocess is performed by exposing the semiconductor layer 512 to anetchant 1202 with the dielectric cap 514 in place over the semiconductorlayer 512. The release etching process removes the first sacrificialregion (e.g., 910 of FIG. 11 ) and the second sacrificial region (e.g.,912 of FIG. 11 ) to form one or more first openings 105 separating oneor more curved cantilevers 106 from a frame 104 and a proof mass 102 bynon-zero spaces. The release etching process also removes the thirdsacrificial region (e.g., 914 of FIG. 11 ) to form one or more secondopenings 107 separating the proof mass 104 from an anchor 108. Therelease etching process also etches the semiconductor layer 512 belowthe one or more first openings 105 and/or the one or more secondopenings 107 to form a lower recess 1204 that extends below parts of theone or more curved cantilevers 106, the frame 104, the proof mass 102,and the anchor 108. In some embodiments, a lower recess 1204 is arrangedwithin the semiconductor layer 512 and extends below parts of the frame104, the proof mass 102, the one or more curved cantilevers 106, and theanchor 108. The lower recess 1204 is in communication with the one ormore first openings 105 and the one or more second openings 107.

In some embodiments, the etchant 1202 is a wet etchant that has a highetching selectivity between the semiconductor layer 512 and thedielectric liner 504. The high etching selectivity causes the etchant1202 to etch the semiconductor layer 512 at a first etching rate whileetching the dielectric liner 504 at a second etching rate less than thefirst etching rate. In some embodiments, the etchant 1202 may comprisehydro-fluoric acid (HF) (e.g., an aqueous HF etch or a vapor HF etch).In other embodiments, the etchant 1202 may comprise hydrogen peroxide(H₂O₂), potassium hydroxide (KOH), or the like

As shown in cross-sectional view 1300 (taken along line 812) andtop-view 1302 (taken along line 808) of FIG. 13 , the lowersemiconductor layer and the insulating layer are removed from thesemiconductor layer 512 to form a MEMS actuator 101. In some additionalembodiments (not shown), the dielectric cap 514 may be removed from thesemiconductor layer 512. In some embodiments, the lower semiconductorlayer, the insulating layer, and/or the dielectric cap 514 may beremoved by way of an etching process, a grinding process, a polishingprocess (e.g., a chemical mechanical planarization (CMP) process) or thelike. In some embodiments, the lower semiconductor layer, the insulatinglayer, and/or the dielectric cap 514 may be removed after attaching animage sensor integrated chip (e.g., shown in cross-sectional view 1400).

As shown in cross-sectional view 1400 (taken along line 1406) andtop-view 1404 (taken along line 1402) of FIG. 14 , an image sensorintegrated chip 202 is placed on the MEMS actuator 101. In someembodiments, the image sensor integrated chip 202 is coupled to theproof mass 102 of the MEMS actuator 101 by way of one or more firstcoupling elements 204. In some embodiments, the one or more firstcoupling elements 204 may comprise conductive structures (e.g., solderbumps, vertical wire bonds, a wire stud, or the like) and/or a polymer.In some embodiments, the one or more first coupling elements 204 may beformed in direct contact with the semiconductor layer (e.g., 512 of FIG.13 ).

As shown in cross-sectional view 1500 of FIG. 15 , the MEMS actuator 101and image sensor integrated chip 202 are placed within a package box 206(e.g., a camera module). The package box 206 comprises a housing 208having sidewalls and an upper surface that surrounds the MEMS actuator101 and the image sensor integrated chip 202. In some embodiments, theframe 104 of the MEMS actuator 101 is physically coupled to sidewalls ofthe package box 206.

In some embodiments, an optical system 214 is disposed along a top ofthe package box 206 at a location directly over the image sensorintegrated chip 202. The optical system 214 may comprise one or morelenses 214 a-214 b that are configured to focus incident radiation ontothe image sensor integrated chip 202. In some embodiments (not shown),the MEMS actuator 101 and the image sensor integrated chip 202 may beplaced within the package box after the MEMS actuator 101 is coupled toa base substrate.

As shown in cross-sectional view 1600 of FIG. 16 , the package box 206and/or the MEMS actuator 101 are coupled to a base substrate 210. Insome embodiment, the base substrate 210 may comprise a printed circuitboard (PCB). In some embodiments, the MEMS actuator 101 may be coupledto the base substrate 210 prior to forming the package box 206 over theMEMS actuator 101. In some embodiments, the MEMS actuator 101 may becoupled to the base substrate 210 by way of one or more second couplingelements 212. In some embodiments, the one or more second couplingelements 212 may comprise conductive structures (e.g., solder bumps,vertical wire bonds, a wire stud, or the like) and/or a polymer. In someembodiments, the anchor 108 of the MEMS actuator 101 may be rigidlycoupled to the base substrate 210 by way of one or more second couplingelements 212.

As shown in cross-sectional view 1700 of FIG. 17 , one or moreadditional integrated chip elements 722-726 are coupled to the basesubstrate 210. In some embodiments, the one or more additionalintegrated chip elements 722-726 may comprise a MEMS gyroscope 722and/or a MEMS accelerometer 724. The MEMS gyroscope 722 and/or the MEMSaccelerometer 724 are configured to sense movement of the package box206 (e.g., during a shaking hand). In some embodiments, the one or moreadditional integrated chip elements 722-726 may further and/oralternatively comprise a control circuitry 726 (e.g., a processor)configured to generate one or more signals to control operation of theMEMS actuator 101 in response to movement of the package box 206. Invarious embodiments, the one or more additional integrated chip elements722-726 may be coupled to the base substrate 210 by way of a bondingprocess, which forms one or more conductive bumps (e.g., solder bumps)between the one or more additional integrated chip elements 722-726 andthe base substrate 210.

FIG. 18 illustrates a flow diagram of some embodiments of a method 1800of forming an integrated chip structure comprising a MEMS actuatorhaving a proof mass coupled to a frame by one or more curvedcantilevers.

While method 1800 is illustrated and described herein as a series ofacts or events, it will be appreciated that the illustrated ordering ofsuch acts or events are not to be interpreted in a limiting sense. Forexample, some acts may occur in different orders and/or concurrentlywith other acts or events apart from those illustrated and/or describedherein. In addition, not all illustrated acts may be required toimplement one or more aspects or embodiments of the description herein.Further, one or more of the acts depicted herein may be carried out inone or more separate acts and/or phases.

At act 1802, a substrate is provided having a semiconductor layerseparated from a lower semiconductor layer by an insulating layer. FIG.8 illustrated a cross-sectional view 800 and a top-view 810 of someembodiments corresponding to act 1802.

At act 1804, a plurality of curved trenches are formed within thesemiconductor layer to separate a cantilever region from a proof massregion and a frame region. FIG. 9 illustrates a cross-sectional view 900and a top-view 928 of some embodiments corresponding to act 1804.

At act 1806, a plurality of straight trenches are formed within thesemiconductor layer and along sides of the proof mass region and theframe region. The plurality of straight trenches are separated from theplurality of curved trenches by sacrificial regions. FIG. 9 illustratesa cross-sectional view 900 and a top-view 928 of some embodimentscorresponding to act 1806.

At act 1808, one or more fill materials are formed within the pluralityof curved trenches and the plurality of straight trenches. FIG. 11illustrates a cross-sectional view 1000 and a top-view 1004 of someembodiments corresponding to act 1808.

At act 1810, the semiconductor layer is patterned to remove the one ormore sacrificial regions and to form non-zero spaces separating acantilever from a proof mass and a frame. FIGS. 11-12 illustratecross-sectional views, 1100 and 1200, and top-views, 1102 and 1206, ofsome embodiments corresponding to act 1810.

At act 1812, the lower semiconductor layer and the insulating layer areremoved to define a MEMS actuator. FIG. 13 illustrates a cross-sectionalview 1300 and a top-view 1302 of some embodiments corresponding to act1812.

At act 1814, sides of the MEMS actuator are coupled to one or moresidewalls of a package box. FIG. 15 illustrates a cross-sectional view1500 of some embodiments corresponding to act 1814.

Accordingly, in some embodiments the present disclosure relates to anintegrated chip structure comprising a MEMS (microelectromechanicalsystems) actuator having a proof mass coupled to a frame by one or morecurved cantilevers.

In some embodiments, the present disclosure relates to an integratedchip structure. The integrated chip structure includes a MEMS(microelectromechanical systems) actuator, including an anchor having afirst plurality of branches extending outward from a central region ofthe anchor, the first plurality of branches respectively including afirst plurality of fingers; a proof mass surrounding the anchor andhaving a second plurality of branches extending inward from an interiorsidewall of the proof mass, the second plurality of branchesrespectively including a second plurality of fingers interleaved withthe first plurality of fingers as viewed in a top-view; one or morecurved cantilevers coupled between the proof mass and a frame, the framewrapping around the proof mass; and the one or more curved cantileversincluding curved outer surfaces having one or more inflection points asviewed in the top-view. In some embodiments, the anchor includes across-shape having the first plurality of branches extending outwardfrom the central region, each of the first plurality of branches beingbent at a 90 degree angle. In some embodiments, the proof mass includesa closed loop wrapping around the anchor. In some embodiments, the oneor more curved cantilevers laterally extend past one or more sidewallsof the second plurality of branches. In some embodiments, the curvedouter surfaces of the one or more curved cantilevers include curvedouter surfaces having a plurality of inflection points.

In other embodiments, the present disclosure relates to an integratedchip structure. The integrated chip structure includes a MEMS actuatordisposed over a base substrate and having a frame coupled to a proofmass by one or more curved cantilevers; an image sensor integrated chipdisposed on the MEMS actuator; and the one or more curved cantileversincluding curved outer surfaces as viewed in a top-view of the one ormore curved cantilevers, the curved outer surfaces having a plurality ofinflection points respectively arranged between turning points as viewedin the top-view. In some embodiments, the MEMS actuator further includesan anchor coupled to the base substrate, the proof mass having a firstplurality of fingers interleaved with a second plurality of fingers ofthe anchor. In some embodiments, the proof mass includes a firstplurality of branches respectively having a first plurality of fingers;and the MEMS actuator further includes an anchor having a secondplurality of branches respectively having a second plurality of fingersinterleaved with the first plurality of branches. In some embodiments,the base substrate includes a printed circuit board. In someembodiments, the frame wraps around the proof mass in a closed loop. Insome embodiments, the one or more curved cantilevers include four curvedcantilevers respectively arranged along a different side of the proofmass. In some embodiments, the one or more curved cantilevers extendfrom a surface of the proof mass that faces a first direction to asurface of the frame that faces an opposing second direction, as viewedin the top-view of the proof mass. In some embodiments, the integratedchip structure further includes a package box surrounding the imagesensor integrated chip and the MEMS actuator, the frame of the MEMSactuator being laterally coupled to a sidewall of the package box; andan optical system having one or more lenses disposed within the packagebox and configured to focus incident radiation to the image sensorintegrated chip. In some embodiments, the integrated chip structurefurther includes a control circuitry disposed on the base substrate andconfigured to generate an electrical signal, the electrical signal beingconfigured to move the proof mass in response to detected movement ofthe package box. In some embodiments, the one or more curved cantileversrespectively have a central region laterally surrounded on opposingsides by cantilever exterior regions, the cantilever exterior regionsincluding a dielectric liner surrounding a core material, as viewed in across-sectional view.

In yet other embodiments, the present disclosure relates to a method forforming an integrated chip structure. The method includes providing asubstrate having a lower semiconductor layer separated from asemiconductor layer by an insulating layer; patterning the semiconductorlayer to form a plurality of curved trenches on opposing sides of acantilever region, a first plurality of straight trenches on opposingsides of a proof mass region, and a second straight trench between aframe region and the plurality of curved trenches, wherein the pluralityof curved trenches are separated from the first plurality of straighttrenches by a first sacrificial region of the semiconductor layer andfrom the second straight trench by a second sacrificial region of thesemiconductor layer; filling the plurality of curved trenches, the firstplurality of straight trenches, and the second straight trench with oneor more fill materials; and removing the first sacrificial region andthe second sacrificial region to form one or more curved cantileversseparated from a proof mass and a frame by non-zero spaces, wherein theone or more curved cantilevers have curved sidewalls that continuouslyextend between the proof mass and the frame. In some embodiments, themethod further includes removing the semiconductor layer from below apart of the proof mass to form a bottommost surface of the proof massthat is separated from the insulating layer by a second non-zero space.In some embodiments, the plurality of curved trenches, the firstplurality of straight trenches, and the second straight trench havebottoms defined by horizontally extending surfaces of the semiconductorlayer. In some embodiments, filling the plurality of curved trencheswith one or more fill materials includes performing a thermal oxidationprocess to form a dielectric liner along sidewalls of the semiconductorlayer defining the plurality of curved trenches; and depositing apolysilicon onto the dielectric liner to completely fill the pluralityof curved trenches. In some embodiments, the method further includesattaching an image sensor integrated chip to the proof mass; andattaching the frame to a sidewall of a package box.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An integrated chip structure, comprising: a MEMS(microelectromechanical systems) actuator, comprising: an anchorcomprising a first plurality of branches extending outward from acentral region of the anchor, the first plurality of branchesrespectively comprising a first plurality of fingers; a proof masssurrounding the anchor and comprising a second plurality of branchesextending inward from an interior sidewall of the proof mass, the secondplurality of branches respectively comprising a second plurality offingers interleaved with the first plurality of fingers as viewed in atop-view; one or more curved cantilevers coupled between the proof massand a frame, the frame wrapping around the proof mass; and wherein theone or more curved cantilevers comprise curved outer surfaces having oneor more inflection points as viewed in the top-view.
 2. The integratedchip structure of claim 1, wherein the anchor comprises a cross-shapehaving the first plurality of branches extending outward from thecentral region, each of the first plurality of branches being bent at a90 degree angle.
 3. The integrated chip structure of claim 1, whereinthe proof mass comprises a closed loop wrapping around the anchor. 4.The integrated chip structure of claim 1, wherein the one or more curvedcantilevers laterally extend past one or more sidewalls of the secondplurality of branches.
 5. The integrated chip structure of claim 1,wherein the curved outer surfaces of the one or more curved cantileverscomprise curved outer surfaces having a plurality of inflection points.6. An integrated chip structure, comprising: a MEMS actuator disposedover a base substrate and comprising a frame coupled to a proof mass byone or more curved cantilevers; an image sensor integrated chip disposedon the MEMS actuator; and wherein the one or more curved cantileverscomprise curved outer surfaces as viewed in a top-view of the one ormore curved cantilevers, the curved outer surfaces having a plurality ofinflection points respectively arranged between turning points as viewedin the top-view.
 7. The integrated chip structure of claim 6, whereinthe MEMS actuator further comprises an anchor coupled to the basesubstrate, the proof mass comprising a first plurality of fingersinterleaved with a second plurality of fingers of the anchor.
 8. Theintegrated chip structure of claim 6, wherein the proof mass comprises afirst plurality of branches respectively having a first plurality offingers; and wherein the MEMS actuator further comprises an anchorincluding a second plurality of branches respectively having a secondplurality of fingers interleaved with the first plurality of branches.9. The integrated chip structure of claim 6, wherein the base substratecomprises a printed circuit board.
 10. The integrated chip structure ofclaim 6, wherein the frame wraps around the proof mass in a closed loop.11. The integrated chip structure of claim 6, wherein the one or morecurved cantilevers comprise four curved cantilevers respectivelyarranged along a different side of the proof mass.
 12. The integratedchip structure of claim 6, wherein the one or more curved cantileversextend from a surface of the proof mass that faces a first direction toa surface of the frame that faces an opposing second direction, asviewed in the top-view of the proof mass.
 13. The integrated chipstructure of claim 6, further comprising: a package box surrounding theimage sensor integrated chip and the MEMS actuator, wherein the frame ofthe MEMS actuator is laterally coupled to a sidewall of the package box;and an optical system comprising one or more lenses disposed within thepackage box and configured to focus incident radiation to the imagesensor integrated chip.
 14. The integrated chip structure of claim 13,further comprising: a control circuitry disposed on the base substrateand configured to generate an electrical signal, wherein the electricalsignal is configured to move the proof mass in response to detectedmovement of the package box.
 15. The integrated chip structure of claim6, wherein the one or more curved cantilevers respectively comprise acentral region laterally surrounded on opposing sides by cantileverexterior regions, the cantilever exterior regions comprising adielectric liner surrounding a core material, as viewed in across-sectional view.
 16. A method of forming an integrated chipstructure, comprising: providing a substrate having a lowersemiconductor layer separated from a semiconductor layer by aninsulating layer; patterning the semiconductor layer to form a pluralityof curved trenches on opposing sides of a cantilever region, a firstplurality of straight trenches on opposing sides of a proof mass region,and a second straight trench between a frame region and the plurality ofcurved trenches, wherein the plurality of curved trenches are separatedfrom the first plurality of straight trenches by a first sacrificialregion of the semiconductor layer and from the second straight trench bya second sacrificial region of the semiconductor layer; filling theplurality of curved trenches, the first plurality of straight trenches,and the second straight trench with one or more fill materials; andremoving the first sacrificial region and the second sacrificial regionto form one or more curved cantilevers separated from a proof mass and aframe by non-zero spaces, wherein the one or more curved cantilevershave curved sidewalls that continuously extend between the proof massand the frame.
 17. The method of claim 16, further comprising: removingthe semiconductor layer from below a part of the proof mass to form abottommost surface of the proof mass that is separated from theinsulating layer by a second non-zero space.
 18. The method of claim 16,wherein the plurality of curved trenches, the first plurality ofstraight trenches, and the second straight trench have bottoms definedby horizontally extending surfaces of the semiconductor layer.
 19. Themethod of claim 16, wherein filling the plurality of curved trencheswith one or more fill materials comprises: performing a thermaloxidation process to form a dielectric liner along sidewalls of thesemiconductor layer defining the plurality of curved trenches; anddepositing a polysilicon onto the dielectric liner to completely fillthe plurality of curved trenches.
 20. The method of claim 16, furthercomprising: attaching an image sensor integrated chip to the proof mass;and attaching the frame to a sidewall of a package box.